PCNL procedures are used to remove kidney stones from a calyx of a kidney. The prerequisite for most PCNL procedures is the establishment of a satisfactory nephrostomy tract, which can be achieved by a urologist using an antegrade approach (from outside a body into the calyx) or a retrograde approach (from the ureter into the calyx). The antegrade approach is most commonly used; however, the retrograde approach can provide numerous benefits to many patients, such as positional advantages that prevent injury, decreased radiation exposure, optimal calyceal selection, and potentially decrease operative time.
Limited visualization discourages the retrograde approach. Fluoroscopy may overcome this limitation, but it only provides a two dimension view of the kidney, making it difficult for the surgeon to determine exactly which calyx has been accessed by the nephrostomy tract. Irrigation techniques are often used in PCNL procedures to flush each calyx. Some of these techniques utilize fluids that can enhance the images by provided by fluoroscopy. Yet, because the kidney naturally drains out into the ureter, these techniques have heretofore proven incompatible with the retrograde approach.
Further improvements are required to make the benefits of the retrograde approach more accessible.